Using an electric mixer, cream the butter, cream cheese and sugar on high speed for 3 minutes.
Add the vanilla and salt and mix at low speed until blended. Mix in the flour at low speed until incorporated.
Divide the dough into thirds; pat into disks. Wrap in plastic wrap; refrigerate for 15 minutes.
Preheat the oven to 350 degrees . Line 2 cookie sheets with parchment. Roll out each dough disk into an 8-inch round. Stack the rounds between pieces of parchment, place on a small baking sheet and refrigerate for 15 minutes. Meanwhile, melt the butter; let cool for 5 minutes.
Place 1 dough round on a floured surface. Using a small offset spatula, spread with 1 tbsp. plus 1 tsp. melted butter; sprinkle with 3 tbsp. chocolate chips and 1 tbsp. granulated sugar. Using a large knife, cut the round into 8 wedges.
Working from the wide end, roll up each wedge and transfer to a prepared pan, spacing evenly and bending in the ends to form a crescent shape. Refrigerate the cookies while you repeat with the remaining dough round, butter, chocolate chips and granulated sugar.
Brush the cookies with egg white; sprinkle generously with sanding sugar. Bake until golden, 22 to 24 minutes. Transfer to racks to cool.
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